ive had creatinine levels higher than that, i thought most doctors were pretty up to speed with trained individuals having raised levels.

as said already, needs retests, and further investigation to make any diagnosis! Dont worry about it too much at this stage mate

And this is part of the problem - eGFR is commonly calculated using creatinine levels, and the equation used to do it is an estimated projection as well as the fact that it does not take into account muscle mass. It is quite well established, for example, that African-American males have eGFRs that for others would indicate CKD, however they are perfectly healthy. The reason for the out of "normal" range eGFR in this case is that African-American males have a higher muscle mass than average caucasian males.

It amazes me that many GPs in this day and age still don't quite understand that muscle mass is directly related creatinine levels. My specialist endocrinologist understands this, and had no concern with my "high" creatinine levels, yet GPs in the past with me have been concerned...

So you have a problem - a high creatinine levels will be skewed by a) increased muscle mass and b) supplementation with creatine supplements. Then take into account that eGFR value is calculated FROM creatinine levels, if your creatinine is high, the eGFR will be low which may indicate a stage of CKD. Thus it is skewed in many cases.

Urea should be measured as should microalbuminuria, which detects protein in the urine that dip sticks cannot detect (i.e. has been sent to the lab for proper analysis).

Based on the fact you've been told no protein in the urine, that you've supplemented with creatine, and that you lift weights with the goal to increase muscle mass, I'd be VERY surprised if you were at any stage of CKD.

that was the second set of blood tests, both come back with high creatinine levels. I had no idea that kidney function was tested by measuring creatinine levels, so i carried on taking my post workout creatine inbetween blood tests - bit stupid really

after the first blood tests results came back i was just told that my 'kidney function was down', and again on the second occasion until i asked to see the results so wasnt aware it was all due to creatinine levels.

have been referred to specialist so will wait and see what he/she says thanks for all the advice

Creatine is unlikely to affect creatinine levels but if you stop taking it for a week you will lose any interference in the test. Using the common Jaffe method my creatinine is the same whether or not I am taking creatine. There is little evidence that higher muscle mass causes higher serum creatinine. The body creatinine is higher but so is the volume of muscle containing it. My creatinine has been the same for 40 years.

Creatine is unlikely to affect creatinine levels but if you stop taking it for a week you will lose any interference in the test. Using the common Jaffe method my creatinine is the same whether or not I am taking creatine. There is little evidence that higher muscle mass causes higher serum creatinine. The body creatinine is higher but so is the volume of muscle containing it. My creatinine has been the same for 40 years.

Why do you say this? This makes little sense to me.

Creatinine is a breakdown waste product of creatine phosphate, which is used in the muscles. Creatinine is a waste product that is excreted through the kidneys with little to no reabsorption. If blood plasma levels of creatinine are high, it is often an indicator of poor clearance of creatinine thus inferred kidney/nephronic damage.

Most in depth studies commonly hold that creatinine is higher in the blood the more muscle mass you have. It has been shown that creatinine levels are lower in vegetarians, generally. Furthermore, this is why creatinine levels are lower in women (who have on average a significant less muscle mass than males).

"Creatinine is mainly derived from the metabolism of creatine in muscle, and its generation is proportional to the total muscle mass. As a result, mean creatinine generation is higher in men than in women, in younger than in older individuals, and in blacks than in whites. This leads to differences in serum creatinine concentration according to age, gender, and race, even after adjusting for GFR. Muscle wasting is also associated with reduced creatinine generation resulting in lower serum creatinine concentration than expected for the level of GFR in malnourished patients with chronic kidney disease. Creatinine generation is also affected by meat intake to a certain extent, because the process of cooking meat converts a variable portion of creatine to creatinine." (emphasis added) [<font]If you follow a higher protein diet, if you train regularly with resistance training and if you consume creatine supplements and have a higher than average LBM, you should a) cease creatine supplementation at least 1 week before and kidney function tests, b) try to have a few days off before tests and c) a practitioner should use a 24-hour creatinine clearance test to calculate eGFR as opposed to a single time-point reading. Additionally the professional interpreting your blood results should take into account your increased muscle mass and resistance training.

In principle both could be right. It's how much of a difference in values that you might argue over. Bottom line is it's outrageous that he was told he had stage 3a without any comment on his training and creatine use.

Creatine is unlikely to affect creatinine levels but if you stop taking it for a week you will lose any interference in the test. Using the common Jaffe method my creatinine is the same whether or not I am taking creatine. There is little evidence that higher muscle mass causes higher serum creatinine. The body creatinine is higher but so is the volume of muscle containing it. My creatinine has been the same for 40 years.

Why do you say this? This makes little sense to me.

Creatinine is a breakdown waste product of creatine phosphate, which is used in the muscles. Creatinine is a waste product that is excreted through the kidneys with little to no reabsorption. If blood plasma levels of creatinine are high, it is often an indicator of poor clearance of creatinine thus inferred kidney/nephronic damage.

Most in depth studies commonly hold that creatinine is higher in the blood the more muscle mass you have. It has been shown that creatinine levels are lower in vegetarians, generally. Furthermore, this is why creatinine levels are lower in women (who have on average a significant less muscle mass than males).

"Creatinine is mainly derived from the metabolism of creatine in muscle, and its generation is proportional to the total muscle mass. As a result, mean creatinine generation is higher in men than in women, in younger than in older individuals, and in blacks than in whites. This leads to differences in serum creatinine concentration according to age, gender, and race, even after adjusting for GFR. Muscle wasting is also associated with reduced creatinine generation resulting in lower serum creatinine concentration than expected for the level of GFR in malnourished patients with chronic kidney disease. Creatinine generation is also affected by meat intake to a certain extent, because the process of cooking meat converts a variable portion of creatine to creatinine." (emphasis added) [<font]If you follow a higher protein diet, if you train regularly with resistance training and if you consume creatine supplements and have a higher than average LBM, you should a) cease creatine supplementation at least 1 week before and kidney function tests, b) try to have a few days off before tests and c) a practitioner should use a 24-hour creatinine clearance test to calculate eGFR as opposed to a single time-point reading. Additionally the professional interpreting your blood results should take into account your increased muscle mass and resistance training.

mcl

I'm perfectly aware of all these equations and have been using them for years in many clinical trials and sports studies.

However there is very little evidence of a link between lean body mass and serum creatinine. Read the following abstract: One of it's authors Professor Swaminathan has a history of actually investigating subjects which are generally assumed to be true with very little evidence.

Relation between plasma creatinine and body size

R Swaminathan, CS Ho, LM Chu and S Donnan We studied the relationship between creatinine concentration in plasma andbody size in 673 healthy individuals (385 women, 288 men). Weight, height,and skinfold thickness were measured and blood was sampled (after a shortfast) for estimations of urea and creatinine in plasma. Lean body mass wascalculated according to Durnin and Wormsley (Br J Nutr 1974; 32:77-97).Concentrations of urea and creatinine in plasma were significantly lower inwomen than in men and were significantly correlated with age in both sexes.For neither sex was there a significant correlation between lean body massand creatinine concentration, even after we took age into account either bymultiple linear-regression analysis or by considering subjects at decadeintervals.

Serum creatinine is lower in vegetarians because they don't eat meat. It increases after a meat meal but not after a vegetarian or milk-based meal. At the very end of your post you quote a suggestion that GFR, in someone taking creatine should be investigated by measuring creatinine clearance. This is also wrong. Excess creatine in urine is converted to creatinine with a half life of about 12 hours. None of the preservatives added to 24 hour urines affects this. A 24 hour urine in someone taking creatine will always have a falsely high creatinine for this reason so when you attempt to calculate the clearance using the formula: Urine volume X urine creatinine / serum creatinine/1440 you will always get a high results since some of the measured urine creatinine is actually derived from the excess creatine supplement. This is one of the reasons I had to advise the abandonment of a study which attempted to measure the amount of creatine absorbed from a supplement derived from genetically modified yeast since the sponsors planned to use serum and 24 hour urine instead uf muscle biopsy assays. It's much harder to get students and sportsmen to volunteer for studies if a muscle biopsy is involved.

Just been to see a specialist at the hospital. She said raised creatinine levels almost defo due to muscle mass, again no blood or protein in my urine sample. Doing a 24 hr urine sample and getting a scan tho, because she saw in my notes that i had problems with pee-ing when i was 15. I didnt like to tell her it turned out it was due to having an STI! Can't beleive my GP actually toldme i have chronic kidney disease. I have respect for Drs, they obv worked really hard to get where they are, but what on earth do they teach them? surely a core principle would be not to tell patients they've got a disease until it's certain

I had a creatinine value of 257 and urea of about 30 at one point. I was in pain and felt awful but survived.

From all i've read taking creatine and higher levels of muscle mass do give higher creatinine results. So the creatinine level is all relative. If you carry a lot of muscle mass then yes creatinine levels may be higher but it does not mean it's out of the normal range for your body. It's just the "average range" values are geared for the average person with average levels of muscle mass. Not a BBer.

The protein in urine is the main concern as mentioned but since you do not have this then i'd guess you're fine.

My high results were caused by (besides creatine/muscle) an OTC drug called metformin (glucophage) + alcohol. Just incase you have used this med before.

nah mate the GP defo said I had stage 3a chronic kidney disease; cos i remember her doing my blood pressure straight afterwards and saying 'it may be higher now since ive given you that bad news'.

I take medication for asthma, sinusitis and acid reflux, i took it all along with me. I'm getting another blood test on monday and i havent taken creatine for a few weeks so will be interested in those results

Just been to see a specialist at the hospital. She said raised creatinine levels almost defo due to muscle mass, again no blood or protein in my urine sample. Doing a 24 hr urine sample and getting a scan tho, because she saw in my notes that i had problems with pee-ing when i was 15. I didnt like to tell her it turned out it was due to having an STI! Can't beleive my GP actually toldme i have chronic kidney disease. I have respect for Drs, they obv worked really hard to get where they are, but what on earth do they teach them? surely a core principle would be not to tell patients they've got a disease until it's certain

You answer your won question in part by not being open and honest. They then have to work at finding out what the cause is. By the same token a GP is, by definition, a GENERAL practitioner and not a specialist.